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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

7392 results found.

  1. GRB 090904B: Swift detection of a burst
  2. GRB 090904: Swift detection of a burst
  3. GRB 090902B: Faulkes Telescope North observations
  4. GRB 090902B: Optical afterglow candidate
  5. GRB090902B: Swift/UVOT observations
  6. GRB 090902B: Swift/XRT Afterglow Candidate
  7. GRB 090831C: Swift detection of a burst
  8. GRB 090831B: Swift detection of a possible burst
  9. GRB 090817 - TLS Observations
  10. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  11. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  12. GRB 090814: Swift detection of a burst
  13. GRB 090813: optical candidate from 1.23m CAHA telescope
  14. GRB 090813: Swift detection of a burst
  15. GRB 090812: Swift detection of a burst with an optical counterpart
  16. GRB 090809: Swift detection of a burst with a possible optical counterpart
  17. GRB 090807: Swift detection of a burst
  18. Swift trigger 358760 is probably a noise event
  19. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  20. GRB 090728: Swift detection of a burst
  21. GRB 090727: Liverpool Telescope possible OT candidate
  22. GRB 090727: Swift detection of a burst
  23. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  24. GRB 090726: optical transient candidate
  25. GRB 090726: Swift/UVOT Finding Chart Observation
  26. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  27. GRB 090709A: deep optical observation with the 10.4m GTC
  28. GRB 090709: Swift detection of a bright burst
  29. GRB 090705: Swift detection of a possible burst
  30. GRB 090628: Swift XRT refined analysis
  31. GRB 090628: Swift/UVOT Finding Chart Observation
  32. GRB 090621B: Gemini spectrum of afterglow candidate
  33. GRB 090621B: P60 Observations
  34. GRB 090621B: Swift detection of a short hard burst
  35. GRB 090621: Swift detection of a burst
  36. GRB 090618: Swift detection of a bright burst with optical afterglow
  37. GRB 090530: RTT150 Optical Observation
  38. GRB 090529A: RTT150 Optical Observations
  39. Initial Swift/UVOT observations of GRB 090531B
  40. GRB 090531B: Swift-XRT candidate afterglow position
  41. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  42. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  43. GRB 090530: Swift detection of a burst with an optical counterpart
  44. GRB 090529: Swift detection of a burst
  45. GRB 090519: Swift/UVOT Upper Limits
  46. GRB 090519: NOT afterglow candidate
  47. GRB 090519: Swift detection of a burst
  48. GRB 090518: Swift detection of a burst
  49. GRB 090516: Swift detection of a burst
  50. GRB 090515: MMT/MMIRS NIR Upper Limit
  51. GRB 090509 - Zadko Telescope observations
  52. GRB 090515: Gemini-N upper limit
  53. GRB 090515: Super-LOTIS Upper Limits
  54. GRB 090515: Swift detection of a short burst
  55. GRB 090510: Swift/UVOT host galaxy candidates
  56. GRB 090510: NOT afterglow confirmation
  57. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  58. GRB 090510: Swift detection of a short hard burst
  59. GRB 090509: GROND afterglow candidate
  60. GRB090429B: Gemini-N infrared IR candidate
  61. GRB 090429B: Swift detection of a burst
  62. GRB 090429: Swift detection of a burst
  63. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  64. GRB 090426: Swift detection of a burst with an optical counterpart
  65. GRB 090423: Swift/BAT spectral lag results
  66. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  67. GRB 090424: Swift detection of a burst with an optical counterpart
  68. GRB 090423 limiting magnitudes
  69. GRB 090423: Near infrared observation at Okayama Observatory
  70. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  71. GRB 090423: NOT z-band limit
  72. GRB090418A Rc-band photometry
  73. GRB090423 - Swift/UVOT upper limits.
  74. GRB 090422: Swift/UVOT Upper Limits
  75. GRB 090423: P60 Observations
  76. GRB 090418A: R and I band observation
  77. GRB 090423: Swift detection of a burst
  78. GRB 090422: Liverpool Telescope possible candidate
  79. GRB 090422: Swift detection of a burst
  80. Swift-BAT trigger 349718 is not a burst
  81. GRB 090417B: Optical observation
  82. GRB 090419: GROND detection of afterglow candidate
  83. GRB 090419: Swift detection of a burst
  84. GRB 090418: Swift detection of a burst with optical afterglow
  85. GRB 090418 OA candidate
  86. GRB 090417A: Early-type nature of the putative host
  87. GRB 090417B: Swift detection of a burst
  88. Swift-BAT trigger 348781: almost certainly not a burst
  89. GRB 090407: Swift detection of a burst
  90. GRB 090404: Swift detection of a burst
  91. GRB 090401B: Swift detection of a burst
  92. GRB 090328: Gemini South Redshift
  93. GRB 090328: Swift UVOT observations
  94. GRB 090328: Updated position/optical afterglow candidate
  95. GRB 090328: Possible Swift/XRT detection
  96. GRB 090323: UVOT Detection of Afterglow
  97. GRB 090313: Swift-XRT refined analysis
  98. GRB 090313, GROND observations
  99. GRB 090313 OA candidate
  100. GRB 090205: Zadko Telescope late-time observations

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